Effect of Parenteral versus Enteral Nutrition on Outcome of Mechanically Ventilated Patient

Abstract

Nutrition is an important aspect of patient care in acute or chronic critical illness. Appropriate nutritional support during the acute phase of critical illness has the potential to reserve or mitigate adverse consequences of poor nutritional status. An increasing nutritional deficit during a long ICU stay is associated with increased morbidity, infection rate, mechanical ventilation, length of stay, duration of recovery, and costs. Mechanically ventilated patient as a critically ill patient is subjected to stress, infection and impaired organ function, resulting in a hyper-catabolic state, leading to metabolic derangement and malnutrition. Critically ill patients are characterized by a number of alterations in carbohydrate, lipid, amino acid, protein and electrolytes metabolism. Nutritional status assessment of the critically ill patient is performed to classify nutritional status, identify nutritional risk and to serve as a baseline for monitoring nutrition support adequacy. It cannot be overstressed that EN is more physiological, safer, and more economic than PN and should be the first choice when feeding critically ill patients and that PN is not without risks. However, many critically ill patients are intolerant to early EN, and among those who are tolerant, most do not receive 100% of their energy requirements because of frequent interruptions to EN. This has been shown in multiple studies that patients received only 50% of what was prescribed,Moreover, cumulative negative energy balances were found to be correlated with increasing number of complications and infections. Given that these patients are highly catabolic, they are at risk of underfeeding with enteral feeding alone. For these reasons, many Studies recommend use PN combined with EN to achieve feeding goals.